Changes in Equity - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2020	Aug. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 966,433	$ 948,394
Income tax effect	(107)	395
Balance	1,529,900	907,441
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(9,142)	(19,639)
Other comprehensive income (loss) before reclassifications	7,608	(3,714)
Reclassification adjustments to income	0	8,496	[1]
Income tax effect	700	0
Balance	(834)	(14,857)
Pension Liability Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(21,886)	(17,856)
Other comprehensive income (loss) before reclassifications	488	62
Reclassification adjustments to income	0	1,242	[1]
Income tax effect	(116)	(291)
Balance	(21,514)	(16,843)
Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(4,189)	(5,969)
Other comprehensive income (loss) before reclassifications	385	(5,659)
Reclassification adjustments to income	2,868	2,334	[1]
Income tax effect	(691)	686
Balance	(1,627)	(8,608)
Accumulated Other Comprehensive Loss, Net of Tax
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(35,217)	(43,464)
Other comprehensive income (loss) before reclassifications	8,481	(9,311)
Reclassification adjustments to income	2,868	12,072	[1]
Income tax effect	(107)	395
Balance	$ (23,975)	$ (40,308)

[1]   (a)  The statement of earnings (loss) classification of amounts reclassified to income include: (1)  Foreign currency translation – result of $7,454,000 related to the sale of the cryogenics business in Turkey; and $1,042,000 related to the impairment of Nisshin, the Company’s former joint venture in China. (2)  Pension liability adjustment – result of the settlement of certain participant balances within the pension plan maintained by WAVE. (3)  Cash flow hedges – disclosed in “NOTE P – Derivative Instruments and Hedging Activities”.